Cp 505

A 1260 Infinity quaternary ultra high performance liquid chromatography (UHPLC) system (Agilent, Waldbronn, Germany) equipped with a binary pump, vacuum-chambered microdegasser, thermostatically controlled autosampler, and column compartment were used in the study. The system was also equipped with a diode-array detector and an Agilent 6540 UHD accurate-mass quadrupole time-of-flight (Q-TOF) mass spectrometer. Electrospray ionization (ESI) was applied in negative ion mode. A full-scan MS was recorded within the mass range m/z 400–1650 and then quadrupole precursor ion selection MS/MS was realized for m/z 50–1650. The following MS/MS parameters were applied: drying gas flow rate 11.0 L min⁻¹; shielding gas flow rate 10.0 L min⁻¹; nebulizer gas pressure 20 psi; skimmer voltage 60 V, octopole voltage 750 V; capillary voltage 4000 V; shielding/drying gas at 350/400 °C; fragmentor voltage 150 V. Nitrogen was used in the ion source and the collision cell. Data were collected using the Agilent Mass Hunter software, version B.04.01.
Sample preparation was performed using a CentriVap vacuum concentrator (Labconco, Kansas City, MO, USA), a model 5424 centrifuge (Eppendorf AG, Hamburg, Germany), a ThermoMixer (VWR, Randor, PA, USA), a laboratory pH meter (Elmetron CP-505, Zabrze, Poland), and Oasis^® HLB columns for solid-phase extraction (60 mg/3 ml; Waters, Milford, MA, USA).

The pH was measured during the fermentation process of bean-based beverages. The pH values of samples were measured directly using the pH meter CP–505 (Elmetron, Zabrze, Poland). The analysis was performed in four replications. The result was read with an accuracy of 0.01 pH unit. On the basis of measurements of pH acidity, curves of acidification of bean-based beverages by individual strains of Lactobacillus were constructed.

The basic chemical composition was determined using DairySpec FT (Bentley Instruments, Chaska, MN, USA). The pH of milk was analyzed using a pH-meter model CP-505 (Elmetron, Zabrze, Poland) equipped with an electrode EPS-1 (Elmetron, Zabrze, Poland). The freezing point of the milk was determined according to ISO 5764 [14 ] using an advanced model 4D3 cryoscope with a 3LH700 thermistor probe (Advanced Instruments Inc., Norwood, MA, USA). The values of dynamic viscosity of the unfermented milk were determined utilizing the method described by Cais-Sokolińska et al. [15 (link)] using a Höppler KF10 viscosity meter by RheoTec Messtechnik GmbH (Ottendorf, Germany).